Trevor Mahelman
After three attempts to complete a critical test of fueling a Space Launch System rocket, NASA decided to take a break.
Space Agency Saturday Night announce plans launch the large SLS rocket from the launch pad at Kennedy Space Center to the Vehicle Assembly Building in the next few days. This represents a significant setback for the program, which since April 1 has attempted to complete a “trial” test, during which the missile is refueled and operational within 10 seconds of launch.
The decision comes after three attempts in the past two weeks. Each refueling attempt was thwarted by one or more technical problems with the missile, mobile launch tower, or ground systems that deliver fuel and gases. During the last attempt, Thursday, April 14, NASA successfully loaded 49% of the primary stage liquid oxygen fuel tank and 5% of the liquid hydrogen tank.
While this is a step forward, it did not include the most dynamic part of the test, during which the rocket is fully refueled and pressurized; Ground and computer systems are put on the final countdown when each variable is closely monitored. NASA was hoping to complete this trial run to figure out the kinks of the complex launch system so that when the rocket launches later this year for the actual launch, the countdown will continue reasonably well.
NASA said its contractors, as well as its agency, will use the next few weeks to resolve issues that arose during refueling tests when the SLS rocket returns to the large vehicle assembly building. For example, Air Liquide, a nitrogen gas system supplier, will upgrade its capabilities. NASA will also replace a faulty check valve in the rocket’s upper stage, as well as repair a leak in the mobile launch tower’s “secret tail service mast”, the 10-meter-tall structure that provides the missile’s thruster and the electrical lines to the block. .
The space agency’s announcement did not provide any information about the effects of the schedule. It seems likely that it will take a week or so to prepare the SLS rocket and return it to the Vehicle Assembly Building. Work on the rocket at that location will likely take at least most of May.
NASA will then have to make some difficult decisions. You can choose to roll the rocket and mobile launch tower onto the platform a second time and attempt to complete the wet test exercise. Then, following normal procedure, NASA will roll the rocket into its assembly building to arm the Flight Safety System, before rolling a third time to the launch pad for takeoff. It appears that the earliest possible launch of the SLS rocket in such a scenario would be in August, but its launch would likely be in the fall.
Another option NASA could pursue is to start testing and completing the wetsuits on the platform, then go ahead and launch them in a few days if that works. In this scenario, NASA could launch the SLS rocket in June or July. However, this can be risky due to the flight safety system.
During a conference call on Friday, Artemis launch director Charlie Blackwell-Thompson confirmed that there is a 20-day deadline once the flight safety system is armed. (This is a range safety mechanism used by all orbital missiles that destroy the booster if it goes off course.) Once the system is activated, it will take about a week to make final preparations in the Vehicle Assembly Building and a week to roll to the launch pad and make preparations there. That would leave just a week for resupply testing, merchandise recycling, and possibly a firing attempt or two before the 20-day window closes.
In other words, this means that the wet dress test must be practically flawless and then the casting attempt must also be flawless. It could also mean that Florida’s summer weather — when there are lots of storms and other extreme conditions — needs to cooperate.
Finally, NASA engineers must balance a number of other factors, such as wear and tear on the rocket, side-mounted ribs exposed on the outside, as well as seemingly endless age considerations with the hardware. For example, agency officials closely monitor the health of fuel in solid rocket boosters, which have been stacked for about 16 months, among other things.
However, NASA seems confident it will get through this painful SLS rocket dent: a program that is now 11 years old and in which NASA has invested more than $30 billion in rockets and ground systems being tested.
“I have no doubt that we will finish this testing campaign, listen to the hardware, the data will take us to the next step,” Blackwell Thompson said Friday. “And we will take appropriate measures and launch this car. I don’t know exactly what that date is, but I have no doubt that we will finish the test drive and be ready to fly.”
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